Bennet woodoeoft



VBENNET WOODCROFT, -OF MANCHESTER, ENGLAND.

SPIRAL IPBOPELLER.

Specification of Letters Patent No.. 4,4%11, dated April 4, 1846.

To all whom t may concern.'

Be it kknown that I, BENNET VooDGRorT, of Manchester, in the county ,of Lancaster, in that part ofthe United Kingdom of .Great Britain and Ireland ycalled England, consult-ing engineer, have invented certain Improvements in Propelling Vessels, ywhich consists, first, in such a combination of the.

blades of what are usually `called screwpropellers, lor of blades which .act in the water as screw-propellers, with other suit.

able apparatus as will when required enable the angle such blades form with the drivingyz shaft or axis upon which they are placed to be changed from a less angle to a greater or from a greater angle to a less, so that .the

vbest pitch of the blades may thereby -be obtained for driving the vessel under varying circumstances, such as alterations in the speed 'of the vessel, in the depth of its `immersion in the water, and in the current of water or wind or of both in which it is actn ing; secondly, in the combination of apparatus with the blades by which they are held to vany required angle with the driving-shaft upon which they are placed or are moved from one angle to another, so as thereby to alter their pitch, and, lastly, in the combination of an indicator with the above-mentioned apparatus and blades so constructed as .at all times to show at what pitch the blades then are or as nearly so as in practice is required.

The nature of my said invention will admitof its being applied to a propeller having any required number of blades and such kblades may be made from portions of a plane or from portions of a screw or from portions of a helix or what is usually .called a screw of increasing pitch or they may be of any shape or of any dimensions capable 'of being moved so .as to alter their pitch las thereto.

admit'of l`the blades the apparatus ,by lwhich the pitch L1s regulated and the indicator being placed in any suitable part of the vessel.

Having now described the nature of Imy said .invention I shall `proceed to show the manner in which the' same may be performed by the following description reference being had to the drawings annexed and the `fi,f r,ures Yand letters marked thereon.

The same letters denote the same parts throughout the drawings.

Figure l represents a portion .of a steam vessel with my improvements attached Fig. 2 represents an Aend view vof the groove box which Aslides upon and vturns around with the shaft and also the cranked ,l .lever and part of the rod by whichsuchfbox` is slid backward yor forward upon theshaft to the lrequired distance. Fig. 3 represents an end view of the propeller shown in Fig.

l. Figs. t, 5 and .v6 show one ofthe blades of the propeller with its arm at .thelower extremity in three different positions.V Fig. 7 shows the periphery of the middle ,blades shown in Fig. -l at three different angles to the driving shaft or axis upon which it is4 placed each of the angles vbeing shown in ,a

different color. ,n

All the above mentioned figures are drawn upon the scale .shown in the drawings. Vhen the periphery of each blade of t-he propeller is at the angle shOWIl by rthe blue line in Fig. 7 the blades will thenbeat or nearly at a seven and a half feet Epitch and provided `no v slip or vrecession Lof the water were to take place by the propeller being turned in the water at the Lrate of one hundred revolutions per minute the propeller would in an hours time lhave passed through a distance of eight miles and ,nine hundred and twenty yards or thereabouts. When the periphery is at the angle shown by the black line the blades will then beat or nearly at an eleven feet ,pitch and Vprovided they were turned at vvone hundred revolutions per minute and provided also that no slip `or recession of the water .were

to take place the propeller at that pitch would in an hours time have passed through a distance of ktwelve lmiles Aand ,a half or thereabouts. And when the periphery is at the angle shown bythe red line the blades `will then beator nearly at a fourteen and a half feet pitch and if they were turned Aunder the same circumstances as to `work upon centers at o.

speed and as to water as in the two preceding' cases the propeller would in an hours time have passed through a distance of sixteen miles and eight hundred and forty yards or thereabouts.

In Fig. 1 A, B, C, I), represent portions of a vessel the part marked A being the stern post of the vessel the part marked B being a portion of the vessel projecting beyond the stern post and over the opening in which the propeller is placed. The part marked C is a false stern post and the part marked D is a continuation of the keel extending under the propeller from the real to the false stern post.

E is a piece of iron which passes on each side of and is united to the pieces A, C, and D to keep them fixed in their places.

F is the driving shaft upon which the propeller and the grooved box are placed. This shaft extends from a bearing or step attached to the false stern post C and through astufing box in the stern post A to 'the driving gear or engine by which it is turned.

a, b, is a boss, or hub keyed fast upon the driving shaft through openings or mortises in the part b, of which the arms d of the blades are passed so as to project over the slidin grooved box. Each of the openings is su ciently wide to admit of the arm being traversed sidewise as much as is required to alter the pitch or angle of the blade with the driving shaft the boss a Z9, on its innerside is made with semicircular slots or openings in which with corresponding slots or openings in the cap o, which screwed on to form circular bearings or steps for the shafts at the bottoms of the blades. When the arms al, and the blades e, are put in their places the cap c, is bolted to the fixed bearing a b, and thereby secures the blades in their working position.

f, is a grooved box placed upon the driving shaft F, which shaft has one or two fixed keys or tongues g, let into it running in the direction of its length. The box f, is placed over these tongues, or tongue and it has a slot, or slots or key grooves l1., in the inside shown in Fig. 2 in which the fixed keys on the shaft enter and by which when the shaft is turned around the box is turned also but these slots and tongues, or keys do not prevent the box from being slid backward or forward on the shaft. On the outside of this box are four oblique grooves z', which receive the heads of the studs j. The round parts of these studs pass through circular openings 7c, (see Fig. 6) in the ends of the arms (Z. Z, is a slot passing around the box f into which two studs m, project (see Fig. 2) xed to the two lower extremities of the bell crank levers n. These levers The p-in which passes through the levers and to which they are keyed works in a bearing of the Ibracket p, which is attached to the stern post of the vessel. Two links g, unite the bell crank levers to the cross head 7'. Through this cross head r, the rod s passes, and it is so attached to that cross head as to turn, or swivel freely around in it or to move it up and down as required. The upper part of this rod passes through the deck the line of which is shown at G, and through a short column H, fixed on the deck. Part of the rod which passes through this column has a worm cut into it so as to form a screw which works in a nut y, fixed in the lower end of the column H. On the top of the rod s, is fixed a wheel I, with handles by which the rod s, can be turned. a, is an indicator with a number of teeth placed concentric with its axis on the one side and having on the other a finger; an index plate showing at what pitch the screw is. This column H, and the indicator are best shown on an enlarged scale at Fig. 8.

is a case which rests upon the worm on the rod s, with a pin' passing through the rod over the case. This case has a rack on one side in which works the teeth of the indicator e.

w, is a key, or check slide fixed to the column H, which takes into a groove behind the case w, and which prevents the case from turning around.

When the wheel at the top of the rod s, is twined so as to force the rod down it will by its action upon the links and bell cranks force the sliding box on the shaft nearer to the propeller and the oblique grooves in the box acting upon the arms of the propeller blades will turn the blades to a less angle with the axis and thereby decrease the pitch of the propeller and when the wheel is turned so as to draw the rod up it, will by it-s action upon the links and bell cranks draw the sliding box farther from the propeller and the oblique grooves in the box acting upon the arms of the propeller'blades will turn the blades to a greater angle with the axis and thereby increase the pitch of the propeller. It will be obvious that `when the rod s, descends or ascends by the screw upon it the case w, also descends or ascends with it and the rack upon it thereby moves the finger of the Aindicator over that part of the plate of the indicator which shows at what pitch the blades of the propeller then are.

Having now described the nature of my said invention and the manner in which I The combination of the blades of propel- 1ers such as I have shown and described With an apparatus for setting the same arpropeller shaft by the turning of a rod s, ranged and operating substantially as hereor by any other equivalent means. in set forth. The sliding box With oblique grooves being made to operate upon arms BENNET WOODCROFT' 5 which are attached to the shaft upon which Witnesses:

the propellers are to turn; said sliding boX JOHN ALCOCK, being made to move back and forth on the THOS. BROWN. 

